While configuring the Data Export Service we got the below error while validating the profile
It mostly occurs if there is some issue with the connection string specified in the PowerShell Script used for generating the key vault.
Always copy the connection string from the Azure SQL Connection Strings property and double check the username and password provided there. And make sure the user specified has all the required rights.
Correcting the connection string resulted in successful validation of the export profile.
Hope it helps..